A marker buoy off the coast of Gulfport, Mississippi, bobs u

A marker buoy off the coast of Gulfport, Mississippi, bobs up and down with the waves. The distance between the highest and lowest point is 6 feet. The buoy moves from its highest point to its lowest point and back to its highest point every 8 seconds. Which of the following equations represents the motion of the buoy if it is at equilibrium when t = 0 and it is moving up from the normal water level.